1. Field Of The Invention
The present invention relates generally to hose clamps, and more specifically to a clamp for stopping the flow of water through a fire hose.
2. Description Of The Related Art
As firefighters carry out their work, the need frequently arises to cut off the flow of water in a hose. This is necessary, for example, when one desires to add or switch a nozzle, a tip, a coupling or another length of hose at a hose's end. Such maneuvers are virtually impossible to carry out on a flowing or pressurized hose. Yet, it is inefficient to shut off the water at the source and to depressurize the entire hose to make an equipment switch or addition at its far end. Instead, the preferred procedure is to clamp off the hose's downstream end, thereby reducing water pressure to zero below the clamp and preserving upstream pressure. Then the equipment is changed or added as necessary, and once the operation is complete the clamp may simply be released for nearly instant restoration of full water pressure.
Clamps are particularly useful to those who fight wildland fires, where end-to-end, 100-foot lengths of hose may commonly be run over one-half mile to a fire site. Likewise, in high-rise buildings, firefighters frequently work 3 to 4 hose lengths from the water source. In these environments it becomes exceedingly inconvenient to return to the upstream end of the hose to halt the flow of water, or to communicate to another to do so, in order to change equipment on the hose's far end.
Many different clamps are known and used for the purpose of temporarily restricting flow in charged fire hoses, but most are rather large, cumbersome and somewhat difficult to use. For example, see the devices of U.S. Pat. No. 3,460,797 issued to Allenbaugh, Jr. in 1969; U.S. Pat. No. 4,582,292 issued to Glotzback, et al. in 1986; U.S. Pat. No. 1,897,743 issued to Warner in 1933; U.S. Pat. No. 2,009,907 issued to Teuber in 1935 and, U.S. Pat. Nos. 2,064,919 and 2,835,525 issued to Kellam in 1936 and 1958, respectively. As wildland and high-rise firefighters must be extremely mobile and able to cover long distances on foot, as well as being self-sufficient and outfitted with a full set of lightweight yet versatile gear, it is apparent from the disclosures of all the above patents that the devices therein are not well-suited for such use.
One genera of relatively lightweight fire hose clamp has arisen to meet wildland and high-rise firefighters' needs, but these too have drawbacks. Examples of these include the "Forestry" hose clamp no. 11213 available from Cascade Fire Equipment Company of Medford, Oregon and the "hose shut off clamp no. 5-360W" (commonly known as the "Sierra" clamp) available from Wajax Pacific Fire Equipment Company of Kent, Wash. Both include a hinged pair of jaws, across the outer ends of which a spanner is hooked to entrap a hose. A lever linked to the spanner is used to draw the hose-grasping jaws together, and a lock ring secures the lever against the outside of one of the jaws. Although such devices are fairly small in size and can be carried in a holster, drawbacks include narrow limits on the hose sizes a single unit may accommodate, and a great risk of injury or damage occurring as such a clamp is released from a charged hose. Further, such clamps are not able to be used on hoses charged with full static pressure; at least a small bit of pressure must be bled off as by letting the hose trickle to permit one of normal strength to fit such clamps in place safely.
And finally, a complicated, two-handed operation is required to install the Forestry and Sierra clamps properly. Thus, it takes new firefighters a considerable amount of time and practice to learn their safe and efficient use.
Accordingly, it appears that currently-available hose clamps do not address the need for a piece of lightweight, handy, versatile, and safe-to-use personal equipment able to be conveniently carried by each member of a wildland or high-rise firefighting engine crew.